Sugarcane is one of the most important global crops with an estimated annual net value of $143 billion (FAO Statistics, 1996). Modern cultivated sugarcane (Saccarum spp, hybrids) belongs to the genus Saccharum, an interspecific hybrid between the domesticated species Saccharum officinarum and its wild relative S. spontaneum. Chromosome numbers of sugarcane cultivars range from 100 to 130 with approximately 10% being contributed by S. spontaneum. 
Interspecific hybridization has led to a huge improvement in sugarcane breeding. It has solved some disease problems, increased biomass yield and sugar yield, and improved adaptability for growth under various stress conditions (Roach et al, 1972, Srivastava et al., 1994). The production of transgenic plants may provide another complementary method for sugarcane breeding. There are various transformation methods that have been developed. Transformation mediated by Agrobacterium has provided a reliable means of creating transgenic plants in many species. Particle bombardment (biolistics) and electroporation have proved to be another successful method with monocots, which are less susceptible to Agrobacterium than dicots. Sugarcane has reliable systems for both transient gene expression and production of transgenic plants. The most commonly used method for transformation of sugarcane is panicle bombardment combined with a herbicide resistance gene as a selectable marker (Gallo-Meagher and Irvine, 1993; 1996; Bower et al., 1992; 1996). Production of transgenic sugarcane plants by intact cell electroporation has also been reported (Arencibia et al., 1995). Recently, Agrobacterium-mediated transfer has been used successfully in sugarcane transformation (Endquez-Obregon et al., 1998; Arencibia et al., 1998).
In spite of reliable techniques for transformation, the expression level of a transgene is still of concern. A DNA construct or vector that drives very high levels of expression is critical in the production of transgenic plants. In general, a transgene vector consists of a very simple construct in which the gene of interest is coupled to a promoter derived from a plant, a virus or a bacterium. Some promoters confer constitutive expression (like ubiquitin and actin), while others may be tissue-specific, wound-inducible, chemically-inducible or developmentally regulated.
The CaMV35S promoter is a well known constitutive and active promoter in dicots, but much less so in monocots. A number of investigations have shown that promoters isolated from monocots show higher activity in monocot species, and that adding an intron between the promoter and the reporter gene increases transcription levels (Wilmink et al., 1995; Ruthus et al., 1993; Maas et al., 1991). The rice actin promoter Act1 (McElroy et al., 1991; Wang et al., 1992; Zhang et al., 1991) and the maize ubiquitin promoter Ubi (Christensen et al., 1992) achieved far better expression than CaMV35S in most monocots tested. Among promoters tested in sugarcane, the Emu promoter and the maize ubiquitin promoter showed better expression than CaMV35S promoter (McElroy et al., 1991; Gallo-Meagher et al., 1993; Rathus et al., 1993). In contrast to cereal crops, in monocots such as tulip, lily and leek, the activities of the monocot promoters were much lower and did not significantly exceed the activity of the CaMV35S promoter. In dicots, the ubiquitin promoter also showed weaker activity than the CaMV35S promoter (Callis et al., 1990; Mitra et al., 1994). Variation in transgene expression levels between different species and promoters may be due to transcription factors, recognition of promoter sequences or intron splicing sites (Wilmink et al., 1995) or other factors. So far, no one has reported the use of promoters or introns from sugarcane itself. Endogenous sugarcane promoters may drive higher levels of expression of transgenes or more stable expression compared to heterologous promoters.
Promoters currently used in monocot transformation are mostly derived from highly expressed genes, such as actin or ubiquitin. The abundance of mRNA can be due to copy number of the gene (GENES V, pp. 703) or to the strength of the promoter (Holtorf et al., 1995). There are no reports indicating what genes are most abundantly expressed in sugarcane, or the gene copy number for abundant messenger RNA in the sugarcane genome. The applicant describes herein newly identified promoters isolated from sugarcane which may prove useful in the expression in monocots of genes of interest.